Figure 14.

Discrimination plot for PP2. The x axis is the number of true column pairs with scores ≤ S for some value S, as a fraction of the total number of true pairs; the y axis is the number of false column pairs with scores ≤ S, as a fraction of the total number of false pairs. The databases were constructed
from the PP2 test set. Shown are discrimination plots for the log-expectation (LE),
log-average (LA), Yona-Levitt (YL), LAMA, and profile sum of pairs (PSP) functions.
The LE function shows higher discrimination over the entire range of scores than any
other function we tested (complete results not shown). The poor performance of the
"standard" PSP function is striking. PSP displays negative discrimination over some
of its range where it falls below the diagonal (dashed line).